Prognostic significance of VEGF immunohistochemical expression in oral cancer: a meta-analysis of the literature

Vascular endothelial growth factor (VEGF) is considered as a prime mediator of angiogenesis and has been implicated in carcinogenesis and metastasis. Various studies examined the relationship between VEGF protein overexpression with the clinical outcome in patients with oral cancer, but yielded conflicting results. Electronic databases updated to March 2013 were searched to find relevant studies. A meta-analysis was conducted with eligible studies which quantitatively evaluated the relationship between VEGF overexpression and survival of patients with oral cancer. Survival data were aggregated and quantitatively analyzed. We performed a meta-analysis of 17 studies (n = 1,207 patients) that evaluated the correlation between VEGF overexpression detected by immunohistochemistry and survival in patients with oral cancer. Combined hazard ratios suggested that VEGF overexpression had an unfavorable impact on overall survival (hazard ratio [HR] = 1.89; 95 % confidence interval [CI], 1.24-2.55) and disease-free survival (HR = 2.08; 95 % CI, 1.14-3.02) in patients with oral cancer: 1.77 (1.09-1.44) in oral squamous cell carcinoma (SCC) patients and 4.28 (1.35-7.21) in adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (MEC) of the salivary glands. No significant heterogeneity was observed among all studies. VEGF overexpression indicates a poor prognosis for patients with oral SCC, ACC, and MEC of the salivary glands.